[PATCH 6.1.y 1/3] scsi: ufs: core: Add a quirk to suppress link_startup_again

[Sasha Levin <sashal@kernel.org>]

From: Adrian Hunter <adrian.hunter@intel.com>

ufshcd_link_startup() has a facility (link_startup_again) to issue
DME_LINKSTARTUP a 2nd time even though the 1st time was successful.

Some older hardware benefits from that, however the behaviour is
non-standard, and has been found to cause link startup to be unreliable
for some Intel Alder Lake based host controllers.

Add UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE to suppress
link_startup_again, in preparation for setting the quirk for affected
controllers.

Fixes: 7dc9fb47bc9a ("scsi: ufs: ufs-pci: Add support for Intel ADL")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251024085918.31825-3-adrian.hunter@intel.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/ufs/core/ufshcd.c | 3 ++-
 include/ufs/ufshcd.h      | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index f9adb11067470..acdad8a79cc10 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -4778,7 +4778,8 @@ static int ufshcd_link_startup(struct ufs_hba *hba)
 	 * If UFS device isn't active then we will have to issue link startup
 	 * 2 times to make sure the device state move to active.
 	 */
-	if (!ufshcd_is_ufs_dev_active(hba))
+	if (!(hba->quirks & UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE) &&
+	    !ufshcd_is_ufs_dev_active(hba))
 		link_startup_again = true;
 
 link_startup:
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 0a56374064856..54bcbfe66163e 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -592,6 +592,13 @@ enum ufshcd_quirks {
 	 * auto-hibernate capability but it's FASTAUTO only.
 	 */
 	UFSHCD_QUIRK_HIBERN_FASTAUTO			= 1 << 18,
+
+	/*
+	 * This quirk indicates that DME_LINKSTARTUP should not be issued a 2nd
+	 * time (refer link_startup_again) after the 1st time was successful,
+	 * because it causes link startup to become unreliable.
+	 */
+	UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE		= 1 << 19,
 };
 
 enum ufshcd_caps {
-- 
2.51.0